What did they ask?

They wanted to investigate whether using piezocision with CAD/CAM customised appliances influenced treatment time of patients with mild crowding.

Piezocision is a relatively invasive method of carrying out flapless corticotomies. Here is a nice video.

When I look at this, I am not sure that this is ‘minimally invasive”.

What did they do?

They did an RCT with a 1:1 allocation. The PICO was:

Participants: 24 adult patients with mild to moderate overcrowding requiring treatment with fixed appliances.Intervention: They did piezocision two weeks after they placed the appliances.Control: Treatment as usual, with no piezocision.Outcome: Overall treatment time.

They fitted all the participants with CAD/CAM-produced self-ligating appliances. They used the following archwire sequence for all the patients; 014, 018, 014X025 and 018×025 Copper NiTi wires and 019×025 ss for finishing. The patients were seen every two weeks. They changed the archwires only when they could achieve full bracket engagement.

Finally, an independent orthodontist validated the appliance removal by reviewing study casts. They were not aware of the group allocation.

The sample size calculation was precise, and they based this on total treatment time. This showed that they needed 11 patients per group. Randomisation was clear, and the treatment allocation was concealed in envelopes. It was not clear whether they registered the participants into the trial before the assignment.

In addition, to treatment duration, they also collected data on the process of treatment and periodontal harms from direct examination and sequential CBCT images.

What did they find?

At the start of the study, there were no differences between the groups. All patients completed the study.

When they looked at treatment duration, the treatment duration in the piezocision group was 278 (SD= 80.2) days. Whereas, for the control group the duration of treatment was 393 (SD= 55.2) days.

This meant piezocision treatment was 1.6 times faster than conventional treatment with a 36% reduction in treatment time. This difference is clinically and statistically significant.

I thought that it was important that the time between archwire changes was significantly lower in the piezocision group for most of the archwires. These differences ranged from about 18 to 43 days.

There were limited or no differences in the other outcomes that they measured. However, the piezocision caused small scars in the gingivae.

In their discussion, they pointed out that there was variation in the findings of other studies. They suggested that this might be due to differences in the piezocision technique, the period between appliance adjustments and appliances.

What did I think?

I think that the results of this study are remarkable. I have previously posted about another study that showed similar results for the time to alignment. However, the results of this study are very clinically relevant because they evaluated the total treatment time. To make this difference clear; I have converted the difference in days to months. This was 3.8 months and is substantial. It is also amazing that one course of piezocision has resulted in such a significant reduction in treatment duration.

Because of this effect size, and I am a real cynic about these methods, I have carefully “taken this study to pieces”. I could not find any significant issues with the study. Most of my concerns are minor, and these are with the unclear method of registration of patients before allocation and the potential lack of power for the secondary outcomes.

However, I did spot that the time between archwire changes was shorter for the piezocision group. This may be a real effect, or as the operators were not blinded to the allocation, they may have been quickly moving up through the wires because they knew that piezocision had been used. This is a potential source of bias, and we need to consider this when we interpret the results.

While we may get excited about this study. We need to be a little cautious. Firstly, the sample size is small and may be subject to individual variation, as evidenced by the difference in standard deviations. We also need to consider whether the difference in treatment time is worth the traumatic procedure. Finally, we need to do more research and include the results of the studies into a meta-analysis. Nevertheless, the results of this paper are interesting and clinically relevant. Piezocision may have a clinical effect.

Have your say!

May I add that it is important to notice the need for multiple small surgeries during the course of the treatment. That may scare or make the cost prohibitive for some patients. Nevertheless and option that could be offered for some patients if proper informed consent in this regard is provided. I do not see my patient population agreeing to it but that does not mean it is not an available alternative based on this promising results.

From 1978 to 1981, I worked in a department which used corticotomies to increase the speed of orthodontic tooth movement in selected cases. The technique was similar to that shown in the video except 1. A labial mucoperiosteal flap was raised. 2. A conventional ‘flat fissure’ surgical but was used. 3. Removable orthodontic appliances were used thereafter.
The technique seemed to be very effective if an experienced surgeon performed the corticotomy.
My main comment on the technique demonstrated in the video concerns making the bone cuts through small vertical incisions.
In a crowded dentition, when roots are just as displaced as crowns there may be a risk of ‘getting lost’ beneath the mucoperiosteum unless the operator is experienced.
In my opinion, it might be safer to reflect a labial muco periosteal flap to allow a more precise visualisation of the roots and where they are going before undertaking the bone cuts. This of course would make for a more invasive but perhaps safer procedure?

When providing any ‘bone injury” surgical or traumatic, the RAP effect is initiated. This results in substantial demineralization of the medullary bone, but not sure of the cortical plates, and thus the tooth/teeth move through a distraction type movement, together with the surrounding demineralized bony matrix.
As a periodontist, providing PAOO for about 20 years, and thousands of treated cases, yes, speed is great, but the most important aspect of the surgery is bony augmentation to accommodate the primary etiology of the crowding, namely, the discrepancy between bone volume and tooth volume, especially in the sagittal direction.
Please refer to my paper JCO, Jan 2019 – Print version Dr’s Gray and Richman, or online version; Dr’s Gray and Richman October 2018.

Thanks for a great blog,
Colin Richman DMD
Practice Limited to Periodontics and especially the Ortho-Perio Interface.

Nice information! Thanks for sharing your experience and research regarding tooth movement with us. This may help in moving the tooth faster and lead to good teeth alignment. I think you have done a great work with this. I would like to know more this process. Keep sharing!Orthodontics Tampa FL